Cytokines and inflammatory bowel disease: a review.

The etiology and pathogenesis of inflammatory bowel disease (IBD) remains an area under intense investigation. Cytokine secretion, which is important in the regulation of normal gastrointestinal immune responses, appears to be dysregulated in IBD. In Crohn's disease, there appears to be an excessive T(H)1 T-cell response to an antigenic stimulus, leading to increased levels of proinflammatory cytokines, such as interferon-gamma (IFN-gamma), interleukin (IL)-12, IL-1, IL-6, and tumor necrosis factor-alpha (TNF-alpha). In ulcerative colitis, a T(H)2 T-cell response appears to be the pathological process responsible for the inflammatory disease. New and innovative therapeutic strategies targeting cytokines, such as TNF-alpha, are producing some promising results in animal and human studies. As more is learned about the complex cytokine interactions in IBD, more effective treatments will undoubtedly ensue.